Calcium is an important element in human diets for adequate bone formation and maintenance as well as other metabolic functions, e.g. nerve transmission, blood clotting, proper cell function and muscle contraction. It is common practice to fortify food products with calcium sources, which are either insoluble or soluble at around neutral pH. Many of the calcium sources currently used for fortification which are insoluble or substantially insoluble at around neutral pH, e.g. calcium carbonate, calcium phosphates, calcium citrate and other organic or inorganic acid salts of calcium, result in precipitation and a chalky mouth feel. Other calcium sources, which are soluble or substantially soluble at around neutral pH such as calcium chloride, calcium hydroxide and a few organic acid salts of calcium, react with milk proteins resulting in undesirable coagulation and gelation.
It is also common practice to stabilize or reduce the sedimentation of the calcium and milk proteins in the milk beverages fortified with calcium sources by adding carrageenans, pectins and/or other gums, but such materials impart an undesirably high viscosity to milk. Protein destabilisation, e.g. coagulation and precipitation, is mainly attributed to free calcium ions in the system.
It would be highly desirable to have a calcium source to fortify milk beverages and other dairy based products without coagulation, gelation and sedimentation, with improved palatability.
In U.S. Ser. No. 08/822,447 now U.S. Pat. No. 5,855,936 there is claimed a fortified foodstuff comprising a fortifying amount of a blend of calcium salts balanced with soluble and insoluble salts stabilized with a source of glucuronic acid. Examples of the soluble calcium salts are calcium lactate and calcium gluconate, calcium glycerophosphate, calcium chloride, etc. Examples of the insoluble calcium salts are tricalcium phosphate, dicalcium phosphate, calcium citrate and calcium carbonate. The weight ratio of soluble to insoluble salts may be from 1:3 to 3:1 and preferably from 1.5:2.5 to 2.5:1.5. However, in the Examples tested for fortifying milk using calcium citrate and calcium phosphate as the insoluble calcium salts, slight sedimentation occurred during milk storage for two months under refrigerated conditions. Also, the use of tri-salt blends requires a large amount of water, as a result of which milk solids have to be adjusted, which cause additional technical and equipment problems (e.g., nonfat dry milk, liquifiers, pumps, more energy, etc). It is desirable to reduce the number of ingredients for easy handling in the factory. It should be also noted that calcium carbonate is less expensive and richer in calcium (40.04%) than a blend of tricalcium phosphate (38.76%) and calcium citrate (24.12%). In addition, we have found that unless the soluble salt in the balanced mixture is calcium lactate, bitterness and off-flavor were found in the milk.